Traditionally, transportation and related services have been provided by a human-operated vehicle. Improvements to computer technology have led to increasing efforts to automate these services, using autonomous vehicles that do not require a human operator. However, riders are accustomed to interacting directly with human drivers to provide information or instructions in addition to the information exchanged in an application for a dynamic transportation matching system. Because the autonomous vehicle lacks a human driver, it may be difficult for passengers to communicate information to the vehicle or receive information from the vehicle. This may undermine the user experience and dissuade potential users from taking rides in autonomous vehicles.